A comparative analysis of the postural and diurnal ocular perfusion pressure of young healthy individuals of different ethnicities

Abstract

Purpose: Ocular perfusion pressure (OPP) regulates the flow of blood to the optic nerve and is determined by the interaction between intraocular pressure (IOP) and blood pressure (BP). Low OPP increases the incidence of primary open-angle glaucoma (POAG). The aim is to compare the diurnal (i.e. morning vs. afternoon) and postural (i.e. seated vs. supine) OPP in healthy individuals from different ethnicities aged between 18 and 30 years.

Methodology: Averaged IOP and BP measurements were obtained with an ICare rebound tonometer and an automated sphygmomanometer, respectively. Measurements were taken in the morning and afternoon, in the supine and seated positions in healthy young adults: Africans (n = 10), white people (n = 10), mixed-race people (n = 10) and Indians (n = 10).

Results: The whole sample (N = 40) displayed a statistically significant reduction in postural and diurnal OPP both in the supine position and in the morning, respectively. A comparative analysis revealed that Africans displayed statistically significant reduction in OPP when compared to other ethnicities.

Discussion: A change in posture to the supine position has a greater impact on the reduction of OPP when compared to diurnal changes. Africans displayed clinically significant reduction in OPP which may increase the incidence of POAG in this ethnicity at an early age.

Conclusion: Our findings question whether OPP should be considered as a biomarker in the dark-skinned individuals. An evaluation of BP and IOP in the supine position is recommended for all patients to obtain more conclusive readings.